Process of producing ammonium sulphate nitrate



Patented Apr. 21, 1931' UNITED(STATES PATENT err-res HERBERT a. Mamas, or rrrrsseaemrumrsnvama, assr'enoa re rumour. rm-

ruman w o1m s or emeaeo rraanors, A coarozm'nou or new mass";

rnoenss or rnobnoiuel Ho Drawing.

Ammonium nitrate istoo-hyprosco 'ieo'r capable of absorbing moisture mos here for direct use as a fertilizer ingre( ient or constituent.

A double salt of ammonium sulphatev and ammonium nitrate is known to the fertilizer industry, and it is less hygroscopic than straight ammonium nitrate, and is, therefore, more readily usable under many coudltions as afertlhzer material.

' Such salt contains about twenty-six and one-half (26.5%) per cent. nitrogen of which approximately, one-fourth ,4,) is in the form of oxidized nitrogen and the remainder ammoni'acah I I have discovered that it is possible and feasible to prepare this double salt by oxidizing ammonia with an excess of air'by, the use of a platinum-gauze catalyst heated electrically or otherwise to the )rope'r temperature o'labout six hundrw (600) to eight hundred (800) degrees contigrade and utilizing the oxides of nitrogen so produced directly in the production of the double salt referred to.

The oxides of nitrogen, together with an excess of air, pass through absorption tow-- ers, through which sulfuric acid circulates until the nitric acid content of the sulfuric acid is built up or increased to the desired uantity, this amount bein preferably such 1 rat about one-fourth /5 of the nitrogen in the finished product is in the oxidized form, and the mixed acids thus formed are then substantially neutralized with ammonia in an ordinary :umnonium-sul )hate saturator, or in any other approvet manner, so

that there are two molecules of ammonia i added for every molecule of sulfuric acid and one molecule of ammonia for each molecule of nitric or nitrous acid, the double salt bein r produced, as will be readily understood, by reason of such neutralization.

'lhe sulfuric acid employed is desirably used as strong as reasonable because it absorbs readily and requires less evaporation, so that the strongest acid from the chamber system. such as sixty degrees Baum, would be used, unless stron er acids from a contact plant were availab e.

rem t e at-:

some summer: manna Application mid, December a, ices Serial no. $124,587.

1. It-isalso possible to repare this double salt bypassing oxides o nitrogen excess air and ammonia gas directly into sulfuric acid circulating countcrciirrent in the absorbing towers, and the solution so formed may be then evaporated to produce the double salt.

Precautions should be taken to condense any fumes escaping from these towers by the use of a Cottrell irecipitator or by the employment of some i orm of filter.

The present invention, as defined by the 'appendml claims, is not necessaril' limited to the precise. and exact details set orth, and these may be modified within a reasonable range without'doparture from the principles of the invention and without the loss of any of its inherent advantages.

1. The process of manufacturing ammonium sulphate nitrate consisting in passing .oxides of nitrogen and airceuntermlrrent to a llow of sulfuric acid to'lorm a mixture of acids, and then substantially neutralizing such mixed acids with ammonia.

2. The process of making ammonium sulphate nitrate consisting in directly introducin oxides of nitrogen, air and ammonia into sull' uric acid.

3Q'lhe process of manufacturing ammonium sulphate nitrate consisting in bringin sulfuric acid into contact with oxides 0 nitrogen and with air, and substantially neutralizing with annnouia the mixed acids thus formed.

In witness whereof I have hereunto set my hand.

I Hllltl5Elt'1 H. MEYERS. 

